The present invention relates to a friction spring unit, particularly for sleeve buffers or push-pull devices of intermediate buffer coupling for rail vehicles.
Friction springs of the above-mentioned application have a plurality of inner rings and outer rings whose conical contact surfaces cooperate with each other with interposition of a lubricant, such as a grease. Such friction springs are known for a long time as components of machines (for example, the friction springs disclosed in the German Pat. No. 1,286,818 or in the U.S. Pat. No. 3,536,314) and are generally utilized in machine-building industry as springs for sleeve buffers of rail vehicles (as disclosed, for example, in the prospectus of "Ringfeder GmbH", C 1059.400.6, issued in May 1972). The friction springs are further utilized in push-pull devices of intermediate buffer couplings which correspond to the regulations of the International Railway Union UIC as disclosed, for example, in the German Pat. Nos. 1,455,252 and 1,455,255 and in the German Offenlegungsschrift No. 2,707,358).
The known friction springs are characterized by high static and dynamic loading capacity and great damping power, and at the same time their service life practically corresponds to the service life of a rail vehicle. In order to attain these properties, dust and moisture must be kept far from the friction spring and its lubricant. It has been recognized from practice that conventional structural parts of the friction spring which receive the latter and serve for transmitting forces, such as buffer sleeves and buffer plungers of sleeve buffers or comparable housings of push-pull devices, not always attain these objects.